The aim of this study is to evaluate the feasibility and the effect of daily, individual, supervised and structured exercise training before radiotherapy in patients diagnosed with Non-Small Cell Lung Cancer. Primary outcome is maximal oxygen uptake (VO2peak). The hypotheses are that patients who undergo daily exercise training will increase VO2peak, functional capacity (measured by 6-minute walk test (6MWD)) and lung function (forced expired volume in one second (FEV1)).